NAME

CallHookPkt: invoke a Hook function callback. (V36)

SYNOPSIS

return = CallHookPkt(hook,object,message);
D0 A0 A2 A1

ULONG CallHookPkt(struct Hook *,APTR,APTR);

FUNCTION

Performs the callback standard defined by a Hook structure. This function is really very simple; it effectively performs a JMP to Hook->h_Entry.

It is probably just as well to do this operation in an assembly language function linked in to your program, possibly from a compiler supplied library or a builtin function.

It is anticipated that C programs will often call a 'varargs' variant of this function which will be named CallHook. This function must be provided in a compiler specific library, but an example of use would be:

result = CallHook(hook,dataobject,COMMAND_ID,param1,param2);

The function CallHook() can be implemented in many C compilers like this:

ULONG CallHook(struct Hook *hook, APTR object, ULONG command, ... )
{

return(CallHookPkt(hook,object,(APTR)&command));

}

INPUTS

hook: pointer to an initialized Hook structure as defined in <utility/hooks.h>
object: useful data structure in the particular context the hook is being used for.
message: pointer to a message to be passed to the hook. This is not an Exec Message structure, but is a message in the OOP sense.

RESULT

return: the value returned by the hook function.

WARNING